Integration of a delta-p expansion valve for cop-optimal regulation in a high-pressure connection, in particular an internal heat exchanger

ABSTRACT

The invention relates to an expansion valve for regulating the mass flow rate by generating a pressure difference on the expansion valve of a refrigeration or heating cycle. Said expansion valve comprises a base ( 31 ) having a through-hole ( 32 ) that is surrounded by a valve seat ( 33 ), and a valve element ( 34 ) which closes the through-hole ( 32 ) and rests within the valve seat ( 33 ) in a closed position and can be moved relative to the valve seat ( 33 ) in the opening direction on the base ( 31 ). The base ( 31 ) is designed to be inserted into a bore section ( 29 ) of an attachment point ( 26, 27 ) of a connection ( 21 ) of an internal heat exchanger ( 14 ) or into a connection ( 21 ) of a pipe in the refrigeration or heating cycle. The outer circumference ( 46 ) of the base ( 31 ) has a fastening section ( 47 ) that is releasably fastened to the attachment point ( 26, 27 ) of the connection ( 21 ) by means of a complementary fastening section ( 48 ).

The invention relates to an expansion valve for mass flow regulation by pressure difference at the expansion valve in a refrigeration or thermal circuit.

An expansion valve is shown in US 2006/0117793 A1, which provides for mass flow regulation in a refrigeration circuit, particularly in vehicle air-conditioning. The expansion valve is inserted in a pipeline section between an internal heat exchanger and an evaporator. For this purpose, the expansion valve has a base body, which includes a through-passage opening, which is surrounded by a valve seat, and which is closable with a valve element in a closed position. This valve element is slidable in the direction of opening to the low pressure side for regulation of the high pressure. The base body of the expansion valve is inserted on the high pressure side in a borehole of the pipeline section, which is adapted for accepting the expansion valve. The expansion valve is secured in its position in the pipeline section by a separate bolted connection.

This arrangement has the disadvantage that, due to the additional bolted connection for securing the expansion valve in the pipeline section, a further bolted connection is required, which connects to the internal heat exchanger. This has the disadvantage that an additional sealing point is required, whereby the impermeability of the refrigerant circuit is reduced. This also results in increased assembly work and material costs.

The object of the invention, therefore, is to propose an expansion valve, which does not necessitate an additional interface or component for insertion into the refrigeration or thermal circuit.

This object is achieved according to the invention by the features of claim 1.

In the embodiment according to the invention of an expansion valve with a base body, which is formed for insertion in a borehole portion of a connector, in particular of the high pressure side connector, of an internal heat exchanger, or in a connector, in particular high pressure connector of a pipeline of the refrigeration or thermal circuit, and comprises an attachment portion on the outer periphery, which is detachably connected in the connector with a complementary attachment portion, has the advantage that a simple and fast assembly of the expansion valve is made possible.

For example, directly in front of the pipe connector on the internal heat exchanger, the expansion valve can be inserted into the connector of the internal heat exchanger or the connector of the pipe connector for attachment to the internal heat exchanger, and subsequently, the pipeline section or its connector are connected to the connector of the internal heat exchanger. Furthermore, in addition to a space-saving arrangement, a design of this type has the advantage that the refrigeration or thermal circuit has one less sealing point, whereby the impermeability of the refrigeration or thermal circuit is increased. Therefore, a reduction in material costs can also be given simultaneously, since an additional housing is not required for accepting the valve element.

According to a preferred embodiment of the invention, it is intended that the attachment portion on the base body is formed as a screw thread. In this way, a simple production of the attachment portion and a quick application can be made possible. When the attachment portion is used as a screw thread, an expansion valve of this type is also called a screw-in cartridge. Alternatively, the attachment portion can also be formed as a bayonet fastening. Therefore, the advantages of a screw thread are also given.

According to a further alternative embodiment of the invention, it is intended that the attachment portion on the base body is preferably formed as a radially aligned supporting surface, which lies on a circumferential, radially aligned annular surface of the borehole portion of the connecting point, with the annular surface bordering a borehole wall of the bore portion. This arrangement has the advantage, therefore, that a simple insertion of the expansion valve in the connecting point of a connector is applicable, and is subsequently adjustable in the connecting point by a further connecting means or similar.

For correct positioning and attachment of the expansion valve in the connecting point, a further energy saving element is preferably provided, which engages with a side of the base body. Opposite, the energy saving element supports itself preferably on a further pipe section, which is attached to the connecting point by an external bolted connection, so that the base body of the expansion valve rests on the annular surface in the bore portion of the connector.

According to a further advantageous embodiment of the invention, on the base body adjacent to the attachment portion, a sealing element is provided, which is preferably provided downstream of the refrigerant to the attachment portion on the base body. The installation security is therefore increased, since the sealing element does not come into contact with the attachment portion on insertion or introduction of the expansion valve into the connector of the internal heat exchanger or the pipeline. Preferably, an O-ring is provided as a sealing element, which is fixedly mounted in a circumferential groove on the base body.

The expansion valve is preferably inserted from the free end of the connector in the bore portion, and preferably in a way so that the base body and the valve element are completely arranged in the connector. Therefore, an expansion valve which is inside the connector of the internal heat exchanger or the pipeline is virtually created, of which the connecting points can stay the same as in the previous embodiment.

According to a further advantageous embodiment of the invention, it is intended that the valve element is pin-shaped, with its valve closure member arranged downstream from the through-passage opening, and the valve element preferably permeates the through-passage opening, so that an energy saving element is provided upstream, which positions the valve closure member in a valve seat. Furthermore, through this arrangement, a very thin and compact embodiment is made possible, so that the expansion valve can also be used in small bore diameters or pipeline diameters. Additionally, the expansion valve is provided with a minimal number of components, namely a base body, a valve element and an energy saving element, as well as preferably with an adjusting nut, a spring seat or an adjusting nut, which form a unit in their assembled position, and thus preferably form a screw-in or push-in cartridge.

According to a further advantageous embodiment of the invention, it is intended that the valve closure member includes a recess as a bypass, singly or multiply spread over its area, which is arranged opposite the valve seat. Through this, it can be achieved that with a closed expansion valve, a leakage mass flow can flow through. Furthermore, this embodiment has the advantage that for a beginning lift of the valve element, the characteristic line regarding the opening cross-section is not influenced, since the recess in the valve closure member is removed from the valve seat.

It is preferably intended, that the at least one recess is formed as a notch. Notches of this type can be easily produced.

According to a further preferred embodiment of the invention, it is intended that the base body comprises a guide section for the valve element, extending upstream of the through-passage opening. Therefore, the valve element can be guided during its opening and closing movement, and a proper closed position of the valve element can be ensured by the through-passage opening.

According to a further preferred embodiment of the invention, it is intended that one end of the energy saving element engages with the guide section. Additional components are therefore not required. In fact, through this arrangement, as well as the preferably one-piece design of the guide section to the base body, a compact embodiment with a reduced number of components can be created, which is fully functional itself.

According to a further preferred embodiment of the invention, it is intended that a spring seat is provided on the adjusting nut, which works as a floating bearing for the energy saving element. Therefore, it can be achieved that the energy saving element works with a lower hysteresis.

According to a further preferred embodiment of the invention, in the opening direction of the valve element an opening cross-section joining the valve seat is intended, which forms a regulator with its outer periphery, independently of the opening position of the valve closure member. In this process, it is intended that the length of the opening cross-section is at least the length of the valve lift, so that a constant regulator cross-section is achieved, independently of the valve lift. Therefore, a post-regulation is achieved, which, in comparison with pre-regulation, has the advantage that gas generation at the regulation point is reduced. This regulator point consequently limits the mass flow for increasing pressures, whereby improved working conditions of the refrigeration or thermal circuit are given.

The expansion valve, which is particularly formed as a built-in cartridge, also has the advantage that the at least one supply opening, which transverses the guide section and leads to the through-passage opening, is provided at an angle between 1 and 90°, with an angle of less than 60° preferably being provided. This means that the supply opening is formed upstream of the refrigerant, so that a smaller change is necessary in the direction of flow. This can contribute to the reduction in gas generation. Therefore, the supply openings point completely or partially opposite the direction of flow, so that the formation of turbulence is reduced.

The invention as well as further advantageous embodiments and developments of the same are described in more detail and explained below by means of the examples illustrated in the drawings. The characteristics to be taken from the description and the drawings can be used individually or as a group in any combination.

IN THE DRAWINGS:

FIG. 1 is a schematic representation of a refrigeration circuit,

FIG. 2 is a schematic cross-section of a connector of an internal heat exchanger,

FIG. 3 is a schematic enlarged view of an expansion valve used in a connector according to FIG. 2,

FIG. 4 is a schematic enlarged view of an arrangement of the expansion valve according to FIG. 2 for post-regulation,

FIG. 5 is a schematic enlarged view of an alternative embodiment of an expansion valve to FIG. 3,

FIG. 6 is a schematic enlarged view of an expansion valve according to FIG. 5 with an alternative attachment in a connector,

FIG. 7 is a diagram for illustration of the effects of post-regulation,

FIG. 8 is a perspective view of an alternative embodiment to FIG. 2.

FIG. 1 shows a refrigeration and/or thermal circuit 11 of an air conditioning system, which is particularly used in vehicles. In a refrigerant compressor 12, a gaseous refrigerant, R134a in particular, is compressed. The compressed refrigerant is led to a condenser 13, where a heat exchange takes place between the compressed refrigerant and the surroundings, in order to cool the refrigerant. Subordinate to the condenser 13, an accumulator 17 can be provided in order to separate refrigerants in the gas phase and the liquid phase, and to simultaneously collect the liquid refrigerant. The refrigerant leaving the condenser 13 or the accumulator 17 reaches an internal heat exchanger 14. An expansion valve 15 is provided between the internal heat exchanger 14 and the evaporator 16. The mass flow of the air-conditioning circuit is regulated by the expansion valve 15, in dependence upon the adjacent pressure difference. From the expansion valve 15, the refrigerant reaches the evaporator 16. In the evaporator 16, the refrigerant takes heat from the surroundings. From there, the refrigerant is again led through the internal heat exchanger 14 to the refrigerant compressor 12.

FIG. 2 shows a schematic enlarged connector 21 of the internal heat exchanger 14. The internal heat exchanger 14 is formed from a double piping arrangement 22, with the external piping cross-section being connected to the condenser 13. The refrigerant is led through the expansion valve 15 to the evaporator 16. The connector 21 has a first connecting point 26, to which a pipeline leading to the evaporator 16 can be connected. The connector 21 has a second connecting point 27 next to this, which leads the refrigerant from the evaporator 16 to the internal heat exchanger 14. From this connecting point 27, the refrigerant reaches the refrigerant compressor 12 through an internal pipeline section 28 of the internal heat exchanger 14.

The expansion valve 15, therefore, is used on the high pressure side, whereby the expansion valve 15 in the bore portion 29 of the first connecting point 26 is used in such a way that a pipeline connection can be connected to the first connecting point 26 without hindrance.

A schematic enlarged view of an expansion valve 15 according to FIG. 2 is shown in FIG. 3. The expansion valve 15 comprises a base body 31, with a through-passage opening 32 with a valve seat 33 bordering it. The base body 31 also absorbs a valve element 34, which has a pin-shaped form, for example, and comprises a valve closure member 36, which closes the through-passage opening 32 in a closed position, which rests on the valve seat 33. For the arrangement of the closed position, an energy saving element 37 is provided, which is arranged with an end on the valve element 34. At the opposite end, an adjusting nut 38 is preferably provided, in order to set the spring biasing force or the opening time of the valve element 34. Opposite this adjusting nut 38, the energy saving element 37 engages with a guide section 39, which is preferably formed as a single component with the base body 31. Usually, the valve closure member 36 is led directly through the guide section 39. In addition, a guide sleeve 41 on the guide section 39 can preferably be provided, in order to guide the valve element 34. Supply openings 43 are provided in the guide section 39, through which the refrigerant reaches the through-passage opening 32. As soon as the high pressure has crossed a certain value, the valve element 34 opens in the direction of flow, that is to say, that the opening movement takes place to the left.

The base body 31 has on its outer periphery 46 an attachment portion 47, which engages with a complementary attachment portion 48, which is provided in the bore portion 29 of the first connecting point 26. In the embodiment according to FIG. 3, the attachment portion 47 is formed as thread, in particular as fine thread. For the adjustment of location or position, a shoulder 50 can be formed on the connecting part 26, in order to ensure a definite position of the expansion valve 15 in the bore portion 29. Upstream of the attachment portion 47, a groove-shaped recess 52 is preferably provided on the base body 31, in which a sealing element 53, preferably an O-ring seal, is arranged. Therefore, a sealing can take place between the bore portion 29 and the base body 31 of the expansion valve 15, so that a tight arrangement is created and no leakage flow develops. Alternatively, in this area a recess or cut-out can be purposely used in order to ensure a defined leakage flow of this type.

The base body 31 comprises an opening cone 55 so that the refrigerant flowing through the through-passage opening 32 can flow out. Downstream of the opening cone 55, a mounting portion 56 is provided, which make it possible, for example, for the expansion valve 15 to be firmly fixed to the connector 21 simply with a tool.

Alternative to the above-described embodiment, it can be intended that the valve element upstream of the through-passage opening 32 closes a valve seat attached thereon.

A schematic enlarged view of a post-regulation through the expansion valve 15 is shown in FIG. 4. In this embodiment, adjacent to the valve seat 33, an opening cross-section 58 is provided, the length of which is at least the length of an outer periphery portion 60 of the valve closure member 36, as well as the lift of a maximal opening movement of the valve element 34. Preferably, the opening cross-section 58 and the outer periphery portion 60 of the valve closure member 36 should be consistently formed, so that a post-regulation is formed, that is to say, that despite increasing lift movement, a consistent regulator cross-section works, and therefore a post-regulation is given, which also limits the mass flow in the through-passage opening 32.

On the valve closure member 36, a recess 45, which is preferably formed as a notch, is provided for forming a bypass 44. This recess 45 is arranged singly or multiply over the area on the valve closure member 36, and preferably lies opposite the valve seat 33. Through this recess 45, which can have a form other than a notch, a so-called leakage mass flow is achieved.

A schematic sectional view of an embodiment of an expansion valve 15 alternative to FIG. 3 is shown in FIG. 5. Subsequently, reference will only be made here to the different form. In addition, the embodiments are applicable to FIG. 3.

In this embodiment, the through-passage openings 43 are not at right-angles to the lift movement of the valve element 34 during an opening and closing movement, but rather inclined in the direction of flow. For example, the through-passage openings 43 are inclined at an angle of 30° to the longitudinal axis of the valve element 34. Therefore an arrangement can be given which is favourable for the flow.

Furthermore, a filter or a screen 65, for example, is provided for this embodiment, which is directly attached by a thread 66 to the base body 31.

Furthermore, in addition to the adjusting nut 38 for the energy saving element 37, this embodiment also comprises, for example, a spring seat 40, which makes a floating bearing of the energy saving element 37 possible, whereby the energy saving element, in particular a spring element, works with a lower hysteresis.

An expansion valve 15 with a structure according to FIG. 5 is shown in FIG. 6. The embodiment according to FIG. 6 differs from that of FIG. 5 in the attachment of the expansion valve 15 to the connector 21. In addition, the previous embodiments apply. Instead of the thread design of the attachment portion 47, 48, this embodiment comprises a stepped bore portion 29 with an annular ring 71, which abuts against the bore portion 29. A support surface 70 is of the base body 31 is supported on this annular ring 71, the support surface also being preferably formed as a radial annular ring. A further energy saving element 74, which fixes the expansion valve 15 into the bore portion 26, engages in an opposite side 73 of the base body 31. The opposite end of the energy saving element 74, which is not shown in detail here, will be held by a further pipeline, which is fixed by an external screwed connection.

A schematic diagram, which shows the effect of the post-regulation, is shown in FIG. 7. From a set opening cross-section, despite further increasing pressure, a bigger opening cross-section cannot be given, as shown by the characteristic line 61. This means that the mass flow stays limited and does not constantly increase, as shown by the characteristic line 62.

An alternative embodiment to FIG. 2 is shown in FIG. 8. In this embodiment, the guide of the refrigerant flow is provided in such a way that the refrigerant admitted with high pressure from the condenser is led through the central channel 28 of the coaxial pipe or double pipe of the internal heat exchanger 14 to the connector 21. After the expansion through the expansion valve 15, which is arranged in the first connecting point 26 of the connector 21, the refrigerant admitted with low pressure flows to the evaporator 16. The refrigerant coming from the evaporator 16 is led through the second connecting point 27 of the connector 21 to the internal heat exchanger 14. In this connector 21 it is suggested, for example, that the expansion valve 15 is inserted frontally. In addition, the embodiments apply to the above-mentioned figures. 

1. Expansion valve for mass flow regulation by a pressure difference in the expansion valve in a refrigeration or thermal circuit, provided with a base body, which comprises a through-passage opening which is surrounded by a valve seat, and with a valve element, which closes the through-passage opening in a closed position and rests in the valve seat, and is moveable in the direction of flow to the valve seat on the base body, wherein the base body is formed for insertion in a bore portion of a connecting point of a connector of an internal heat exchanger, or in a connector of a pipeline in a refrigeration or thermal circuit, and comprises on the outer periphery of the base body an attachment portion, which is detachably mounted with a complementary attachment portion to the connecting point of the connector.
 2. Expansion valve according to claim 1, wherein the attachment portion is formed as a screw thread or bayonet fastening.
 3. Expansion valve according to claim 1, wherein the attachment portion on the base body is formed as a support surface, which rests on a circumferential, preferably radially aligned, annular ring, which is formed as an attachment portion, and is bordered by a bore portion.
 4. Expansion valve according to claim 3, wherein an energy storage element engages with one side of the base body, and fixes the base body to the annular ring.
 5. Expansion valve according to claim 1, wherein on the base body adjacent to the attachment portion, a sealing element is provided, which is preferably arranged downstream of the refrigerant to the attachment portion of the base body.
 6. Expansion valve according to claim 1, wherein the base body is completely useable from the free end of the connecting point of the connector.
 7. Expansion valve according to claim 1, wherein the expansion valve has a pin-shaped form, with its valve closure member being arranged downstream of the through-passage opening, and that the valve element preferably permeates the through-passage opening, whereby an energy saving element is provided upstream, which positions the valve closure member in the valve seat.
 8. Expansion valve according to claim 1, wherein the valve closure member comprises once or several times over its extent spread as a bypass a recess, which is arranged on the valve closure member opposite the valve seat.
 9. Expansion valve according to claim 8, wherein the at least one recess is formed as a notch.
 10. Expansion valve according to claim 1, wherein the base body comprises a guide portion for the valve element extending upstream of the through-passage opening.
 11. Expansion valve according to claim 1, wherein one end of the energy saving element engages with the guide portion, and the opposite end engages with the valve element or an adjusting nut arranged thereon.
 12. Expansion valve according to claim 8, wherein a spring seat is provided on the adjusting nut, which preferably works as a floating bearing for the energy saving element.
 13. Expansion valve according to claim 1, wherein in the opening direction of the valve element on the valve seat an opening cross-section is then provided, which forms a regulation point, independent of the opening position of the valve closure member between the outer periphery of the valve element and the opening cross-section.
 14. Expansion valve according to claim 1, wherein the at least one supply opening to or for the through-passage opening is provided at an angle of between 1° and 90°, with an angle of preferably less than 60° in relation to the longitudinal axis of the valve element. 